高地应力软岩隧道围岩压力及二衬受力特征研究

Study on Surrounding Rock Pressure and Mechanical Characteristics of Secondary Lining in Weak Rock Tunnel with High Geo-stress

为研究高地应力条件下软岩隧道围岩压力作用规律及二衬受力特征,依托兰新铁路第二双线大梁隧道,分别对隧道围岩与初期支护、初期支护与二次衬砌之间的接触压力进行现场监测,得出上述压力随时间变化规律和沿隧道横断面分布特征,基于实测围岩压力对隧道二次衬砌结构内力进行计算。研究结果表明：初支围岩压力和初支与二衬接触压力随时间发展呈不同变化规律;围岩压力在空间分布上表现出＂两侧大、拱顶小＂的侧向挤压特征;二次衬砌围岩压力分担比例平均值在45.0%~70.3%;实测围岩压力较规范围岩压力计算出的二衬内力更符合实际。

In order to study the soft rock pressure and mechanical characteristics of secondary lining in weak rock tunnel with high geo-stress,the Daliang tunnel on the second double-track line of new Lanzhou~ Xinjiang railway is based to monitor the contacting pressure on surrounding rock and the initial lining and the contacting pressure between the initial lining and the secondary lining,and the development law over time and the spatial distribution of contacting pressure are obtained. The internal force of the secondary lining structure is calculated based on measured surrounding rock pressure. The study results show that the two kinds of pressures change differently over time; the contacting pressure is larger on both sides,smaller in vault,which indicates an obvious lateral extrusion; the secondary lining bears the average of 45. 0% ~ 70. 3% of the surrounding rock pressure; the measured surrounding rock pressure is more practical than the internal force of the secondary lining calculated based on specified surrounding rock pressure.